In an arrangement of this type known from EP-PS 29512 the end areas of the LWG from which the primary coating has been removed are laid loosely in guide grooves of a holder and are clamped there with their rear area. In the front area they engage a rubber insert member which is to produce the pressure in the guide groove of a guide element. The two holders are pressed against each other by means of a coil spring so that at the same time the end faces of the two LWGs closing the end faces of the holder satisfactorily are laid against each other. In the coupling process the ends of the LWG must be guided through the guide groove of the guide element against the frictional force caused by the pressure of the insert element. In particular the end faces of the LWG can be damaged. Moreover the threading of the LWG in the guide groove produces considerable difficulties, in particular because the LWGs before inserting in the guide grooves of the guide element are forced up from their holder by the rubber insert elements.